Event Collector 
Event Collector
Definition
An event collector is a quantity of several events that have been successfully completed independently of each other, to which background processing should respond.
The event collector corresponds to the AND process and the process chain maintenance. If an application process is scheduled via an event collector, it starts when all events for the preceding process were successfully triggered.
In order to clarify the difference between a process chain and an event chain as AND-
Use
You can collect events for an event collector in the Administrator Workbench. If all the events contained in a chain have been activated and the chain has thus been successfully processed, then a successful event is triggered that has been previously determined in the subsequent processing of the event collector.
You can trigger processes by activating this event. Event collectors are used to control processes in BW.
Integration
Events triggered by event collectors can be used as a trigger for a process chain. Furthermore, it is possible to combine event collectors with process chains by their own programming. Thus, it is generally possible to integrate event collectors in process chains.
In BW 3.0, automatic process control has been enhanced and improved significantly with the concept of process chains. Process control using post-processing events and event collectors is not functionally enhanced but it is still supported. We recommend that you only use process chains for schedules of connected processes that must be re-defined.